The study of mechanisms used for speech perception will be continued using a number of auditory phenomena and procedures developed in the principal investigator's laboratory (which include verbal transformations, phonemic restorations, spectral restoration, vowel conversions, and phonemic splitting). The aim is to examine linguistic mechanisms not readily accessible through other means. It is anticipated that the information obtained will be of help in elucidating mechanisms associated with the coding, processing, storage and retrieval of information necessary for the comprehension of speech, and should aid in understanding the etiology of dysphasias and aphasias, as well as enhancing the diagnoses and treatment of these disorders. In order to design multichannel cochlear implants that can restore hearing in deaf individuals and permit them to comprehend speech, it is necessary to have accurate data describing the information content of different spectral regions, and how they interact when combined. The principal investigator's laboratory has developed a procedure capable of obtaining such data directly, which if this application is funded, will be gathered and used to evaluate, and provide an alternative to the estimates derived from the indirect procedures in current use.